Previous work has suggested that functional reorganization of cortical
areas might have a role in limiting the clinical impact of axonal pathology
in patients with established multiple sclerosis (MS).

Since there is evidence
for irreversible tissue damage even in patients with early MS, we assessed,
using functional MRI (fMRI) and a general search method, the brain pattern
of movement-associated cortical activations in patients at presentation
with clinically isolated syndromes (CIS) suggestive of MS.

To elucidate
the role of cortical reorganization in these patients, we also investigated
the extent to which the fMRI changes correlated with the extent of overall
axonal injury of the brain.

From 16 right-handed patients at presentation
with CIS and 15 right-handed, age- and sex-matched healthy volunteers,
we obtained: (1) fMRI (repetitive flexion-extension of the last four fingers
of the right hand), (2) conventional MRI scans, and (3) a new, unlocalized
proton MR spectroscopy ((1)HMRS) sequence to measure the concentration
of N-acetylaspartate of the whole brain (WBNAA).

This study shows that axonal
pathology and functional cortical changes over a rather distributed sensorimotor
network occur in patients at presentation with CIS suggestive of MS and
that these two aspects of the disease are strictly correlated.

This suggests
that the increased functional recruitment of the cortex in these patients
might have an adaptive role in limiting the clinical impact of irreversible
tissue damage.